[d8] Park thread before blocking in semaphore

We need to park the isolate's main thread before blocking in the
semaphore to allow a shared GC to happen in the meantime.

Bug: v8:11708, v8:12647
Change-Id: Ide215d2c811caee84663d8749b7d94a414c44bd8
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3485678
Auto-Submit: Dominik Inführ <dinfuehr@chromium.org>
Reviewed-by: Camillo Bruni <cbruni@chromium.org>
Commit-Queue: Camillo Bruni <cbruni@chromium.org>
Cr-Commit-Position: refs/heads/main@{#79261}

src/d8/d8.cc

@@ -4010,7 +4010,11 @@ void SourceGroup::ExecuteInThread() {
   Shell::Initialize(isolate, &console, false);
 
   for (int i = 0; i < Shell::options.stress_runs; ++i) {
-    next_semaphore_.Wait();
+    {
+      i::ParkedScope parked_scope(
+          reinterpret_cast<i::Isolate*>(isolate)->main_thread_local_isolate());
+      next_semaphore_.Wait();
+    }
     {
       Isolate::Scope iscope(isolate);
       PerIsolateData data(isolate);